Field of the Invention
The present invention relates to a leak detection method of a reducing agent pumping system that pumps a reducing agent safely and pleasantly by pumping a reducing agent stored in a reducing agent tank to an injector and rapidly detecting leak of the reducing agent in the pumping.
Description of Related Art
At present, a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF), a nitrogen oxide purifying unit (LNT, lean NOx trap), and a selective catalytic reduction unit (SCR) have been considered in diesel engines of vehicle to cope with the exhaust gas regulations.
Particularly, in the requirements of exhaust gases in Europe, ARTEMIS mode is examined instead of NEDC mode, which is a typical actual high-speed running condition. In the actual high-speed running condition, since the DOC+DPF+LNT system exhausts nitrogen oxide (NOx), there is a need of a method of reducing nitrogen oxide.
Accordingly, the selective catalyst reduction system is used, which reduces nitrogen oxide by spraying urea, which is a reducing agent, to the front of a catalyst.
In order to effectively spray urea that is a reducing agent, a pumping pressure of about 9 bar is required, and the reducing agent pumping system may stop when the pumping pressure drops. Bubbles flowing in the pumping line or malfunction of a pressure sensor may stop the reducing agent pumping system.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.